Cognitive functional status measures are critical tools for research on the effectiveness of rehabilitation interventions for traumatic brain injury (TBI). Global functional measures are widely used in rehabilitation settings, but only provide a cursory evaluation of cognition. Traditional neuropsychological measures, while standardized and psychometrically sound, are lengthy and often criticized for having weak ecological validity. The purpose of this project is to build an ecologically valid item bank and computer adaptive testing (CAT) prototype for an applied cognitive measure for TBI. Modern test theory provides a basis for developing a measure that is both efficient to administer and precise for assessing cognition along the continuum of TBI recovery. Item Response Theory methodologies, specifically Rasch analysis, can be used to calibrate items thereby providing a means to match item difficulties to cognitive ability levels across stages of TBI recovery. CAT technology provides a mechanism to administer a small number of items to an individual, based on his/her cognitive ability level. This planning proposal will accomplish the following: First, conduct literature reviews of existing instruments and theoretical models of TBI recovery to guide creation of a large item bank (300-500 items) reflecting cognitive behaviors commonly observed throughout TBI recovery. Second, health care professionals, patients and caregivers will be interviewed to expand and fine-tune the item bank. Third, a paper and pencil version of the instrument will be pilot tested on 50 patients in acute hospitalization, inpatient/outpatient rehabilitation and 6-months post rehabilitation. Self-report, therapist and caregiver administrations of the instrument will be compared to a "gold standard" abbreviated neuropsychological assessment to identify the most appropriate rater at each stage of recovery. Finally, a web-based CAT prototype of the instrument will be developed and administration feasibility will be determined by feedback following healthcare professional, patient and caregiver administration. This planning grant will result in the item and CAT development necessary for reliability, validity and sensitivity testing of the TBI cognitive measure in a multicenter trial. The long-term objective is to develop an efficient, precise and ecologically valid instrument to evaluate outcomes of TBI interventions.